separation techniques

• soluble

  able to dissolve
• insoluble

  unable to dissolve
• filter paper has small holes that are large enough to allow liquid particles to move through but too small to allow solids through - this separates the solids from the liquids in filtration
• steps of fractional distillation

  
  

  1. heat is applied and the liquid with the lowest boiling point evaporates and condenses into a beaker
  2. if other liquids evaporate by chance, they condense in the fractionating column back into the flask
  3. the temperature is altered to repeat the process for the second liquid
  4. the three liquids are separated based on differing boiling points with the third remaining in the flask
• dissolve

  when a substance breaks up and mixes completely with a solvent to produce a solution
• solubility

  the ability of a solid, liquid, or solute to dissolve in solvent
• filtrate

  a liquid which has passed through a filter
• crystallisation

  1. a solution is placed in an evaporating basin and heated with a bunsen burner
  2. the volume of the solution has decreased because some of the water has evaporated and solid crystals begin to form in the basin
• filtration

  1. one beaker contains a mixture of solid and liquid, the other contains a funnel with filter paper
  2. the insoluble solid and liquid mixture is poured into the filter funnel
  3. the liquid drips through the filter paper but the solid particles are caught in the filter paper
• paper chromatography

  1. water and ethanol solution is heated
  2. as the paper is lowered into the solvent, some of the dye spreads up the paper
  3. the paper has absorbed the solvent and the dye has spread further up the paper
• solute

  dissolved solid
• physical processes

  • don't create new chemical substances (there are no chemical reactions)
  • examples: chromatography, filtration, crystallisation, simple distillation and fractional distillation
• distillation

  • physical separation technique
  • separates mixtures of liquids and uses the different boiling points of liquids to separate them
  • collects the solvent instead of allowing it to evaporate (into the air)
  • can be simple or fractional
• solution

  a liquid (solute) that contains a dissolved solid (solvent)
• ways to speed up dissolving

  • heating
  • stirring
  • using fine powders
• solvent

  a liquid in which substances can dissolve
• chromatography

  • type of physical separation technique
  • separates solutions with a number of different solutes (solids) in the solvent (liquid)
• simple distillation

  • physical separation technique
  • separates 2 liquids (a dissolved liquid from a liquid) with different boiling points and keeps the liquid
  • can be used to produce drinking water (from sea water)
  • crystals of solid are left in the flask

  
• steps of simple distillation

  1. a solution is heated until it boils (using a bunsen burner)
  2. the liquid starts to evaporate and turns into a vapour (which increases the thermometer reading)
  3. the gas is cooled (by a water jacket) and condenses into a liquid
  4. the liquid is collected in a beaker
• fractional distillation

  • physical separation technique
  • separates multiple liquids with different boiling points

  
• paper chromatography

  • physical separation technique
  • allows substances to be separated based on their solubilities
  • the paper is stationary and the solvent is mobile
  • a simple compound will produce a single spot in all solvents whereas the compounds in a mixture separates into different spots
  • the more soluble a substance is, the further it will travel up the paper
  • can be used to identify an unknown substance

  
• crystallisation

  • physical separation technique
  • separated the dissolved solid (solute) and liquid (solvent)
  • produces solid crystals from a solution by evaporating the solvent

  
• filtration

  • physical separation technique
  • used to separate an insoluble solid from a liquid
  • insoluble solid is trapped and the liquid runs through the paper (and is collected below)